Makeup compositions are products such as a foundation, an eye shadow, a blush, an eye liner, an anti-eye-ring product, a body makeup product, a lip makeup product, a mascara, etc. In addition to a fat phase and an aqueous phase, this type of composition generally contains organic or mineral fillers and coloring agents as well as various other potential additives such as surfactants, a film-forming polymer, etc.
In addition to the dermatological virtues of such compositions, their primary purpose is to provide aesthetic properties at the level of the body surface to which they are applied. It may be to eliminate certain skin defects, to lighten or darken it, give a particular shade or shades. In most cases, the coloring obtained, and especially the intensity of this color is a determining factor in describing the quality of a product such as a foundation.
In addition to the satisfaction of the end user who gets the shade desired, the ability to deliver the desired color with maximum intensity right from the first application will impact the useful life of the product: through a single application, the consumption of the product is reduced.
For such a composition which contains coloring agents as explained above, the intensity of the color delivered at the level of the surface of the skin or eyelashes is reflected in an indirect way through the magnitude L, the first coordinate in the colorimetric standard well known to the person skilled in the art, (L, a, b) as defined by the International Commission on Illumination (ICI).
L defines the brightness, which ranges from 0 (black) to 100 (white). Therefore, for a given hue such as that supplied by pigments, fillers and coloring agents, the higher the value of L, the more the color is attenuated, because it tends toward white. Conversely, a low value of L is associated with a more pronounced coloration, i.e., one that is more intense. The value of L is determined in this Application on a cosmetic composition as such, or on the film resulting from the application of such a composition.